Whenever you take an ECG on the Apple Watch, there’s a prominent warning that Apple Watch never checks for heart attacks.
Apple Watch does not check for heart attacks using its ECG (it does check for abnormal heart rhythms)
In this post, we’ll explain which heart conditions the Apple Watch ECG can detect, blood tests and imaging that do predict heart attack risk, and how to use Apple Watch as part of a comprehensive heart health plan.
Apple Watch’s ECG detects abnormal heart rhythms
Apple Watch’s ECG (electrocardiogram sensor) is FDA-cleared as a medical device to detect the most common abnormal heart rhythm, atrial fibrillation. Atrial fibrillation causes 1 in 4 strokes. In addition, Apple Watch’s heart rate monitor has an FDA clearance to alert people to likely atrial fibrillation via irregular rhythm notifications.
An irregular rhythm notification on Apple Watch, for an abnormal heart rhythm (not heart attack)
If you get an irregular rhythm alert, take it seriously. In the Apple Heart Study, 84% of participants who received an irregular rhythm notification while wearing an ECG patch were found to have atrial fibrillation.
Why Apple Watch’s ECG cannot detect heart attacks
Apple Watch’s ECG may show some, but not all, heart attacks. This is why you can’t rely on the Apple Watch ECG to detect a heart attack.
A heart attack happens when bloodflow to part of your heart is stopped. Even with hospital equipment, it’s possible to have a normal ECG but elevated troponin.
Hospital equipment is a 12-lead ECG, which measures electrical activity in 12 “angles” through the heart. Depending on which part of the heart is affected, some leads may show abnormalities and other leads will appear normal. Apple Watch’s ECG is only 1 lead, so it may miss many heart attacks.
Heart attack risk can be predicted with blood biomarkers
While Apple Watch can’t predict a heart attack, blood tests can. It’s possible to predict both your lifetime and 10-year risk of a heart attack by using blood biomarkers like ApoB, LDL and HDL cholesterol, a1c, and your blood pressure.
Empirical Health’s advanced cardiovascular panel includes all the biomarkers you need to predict heart attack risk for under $200. It includes advanced heart health biomarkers such as ApoB, Lp(a), lipid particle size, LDL, HDL, total cholesterol, and 50+ other numbers.
During a heart attack, doctors use a 12-lead ECG and blood tests
When a patient arrives in the emergency room with a suspected heart attack, doctors use several tools to confirm a heart attack. First, they use a 12-lead ECG (placed on the chest, back, arms, legs) to view electrical signals that show many “angles” through of the heart. If they see that the ST segment (one part of the ECG) is elevated, then they know the patient is having a type of heart attack called a STEMI (ST elavation myocardial infarction). Second, they perform a blood test for troponin, a protein which is released when heart muscle is dying. Dependong on the results, the doctors will give the patient different types of treatment: clot-busting drugs, coronary artery bypass graft (CABG) surgery, stenting, and so on. Needless to say, if you’re currently having a heart attack, please call 911.
Research showed the Apple Watch’s ECG can be used as a 9-lead ECG for heart attack detection
Researchers at the Texas Heart Institute came up with a clever proof-of-concept study that uses the Apple Watch as a 9-lead ECG. In their study, participants wore the Apple Watch in a variety of different positions on the chest, arms, legs, and so on:
While this approach is very clever, it’s not necessarily a practical way to use an Apple Watch during a heart attack in the real world.
How to use your Apple Watch for comprehensive heart health
Do you want to create a comprehensive plan to improve heart health, including advanced biomarkers, nutrition, exercise, and medication? Download Empirical Health for Apple Watch or Android in order to create your customized plan.
